Blade ring support



March 3, 1970 Filed Jan. 24, 1968 J. A. MARTIN, JR,, ETAL BLADE RING SUPPORT 2 Sheets-Sheet 1 FlG.l

FIG.2

WITNESSES a fi I James INVENTO rtin,Jr., HerbenAHi e 6 ge lg Bollinger, Jr.

March 3, 1970 J. A. MARTlN JR, ETAL' 3,498,727

BLADE RING SUPPORT- 2 Sheets-Sheet 2 Filed Jan. 24, 1968 FIG. 3

l I I United States Patent 3,498,727 BLADE RING SUPPORT James A. Martin, Jr., Newtown Square, Herbert A. Hickey, Ridley Park, and George R. Bollinger, Jr., Swarthmore, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennnsylvania Filed Jan. 24, 1968, Ser. No. 700,252 Int. Cl. F01d 1/00, 9/00 US. Cl. 415136 13 Claims ABSTRACT OF THE DISCLOSURE Blade rings of a turbine are adjustably supported in the turbine outer cylinder or casing on dowel pins which rest on liners in the casing in a manner to provide for differential thermal expansion between the blade rings and the casing. The head of each dowel pin has four fiat surfaces each machined to a dilferent dimension from the dowel center line to provide adjustable elevation alignment of the blade ring relative to the outer cylinder by rotation of the dowel to the desired head position.

BACKGROUND OF THE INVENTION This invention relates to elastic fluid utilizing machines and particularly to steam turbines of the axial flow type.

In an axial flow turbine having a series of expansion stages, blade rings containing stationary blades which cooperate with blades carried by the turbine rotor may be mounted in the outer cylinder or casing of the turbine. The casing and the blade rings are split along a horizontal plane into upper and lower half portions. In order to permit differential thermal expansion between the blade rings and the casing, it is necessary to provide a movable support for the blade rings in the casing. Also, it is necessary to maintain proper clearance between the stationary blades and the rotor blades during operation of the turbine.

A prior method of supporting steam turbine blade rings in the outer cylinder or casing is by bolting a separate key to each side of the blade ring base half. Each key rests on a liner bolted to the outer cylinder. The costly key design requires special fitting to the blade ring halves. Also, expensive machining is incurred in the blade ring for the key slot.

An object of this invention is to simplify the structure and reduce the cost of manufacturing and installing blade ring supports for elastic fluid utilizing machines, such as steam turbines.

Another object of the invention is to provide for adjusting the elevation alignment of each blade ring rela tive to the outer cylinder or casing of a turbine.

Other objects of the invention will be explained hereinafter or will be apparent to those skilled in the art.

SUMMARY OF THE INVENTION In accordance with one embodiment of the invention, the outer cylinder or casing and the blade rings of a turbine are split along a horizontal plane into upper and lower half portions. Circular dowel pins are secured in the base portion of each blade ring. The pins extend outwardly horizontally along a plane parallel to the vertical plane of the ring and their heads rest on liners disposed in recesses 3,498,727 Patented Mar. 3, 1970 ice BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is an isometric view of a portion of a steam turbine embodying principal features of the invention;

FIG. 2 is an enlarged fragmentary detail view in vertical section, of one of the blade ring supports utilized in the structure shown in FIGURE 1;

FIG. 3 is a View, in section, taken along the line III- III in FIG. 2, and

FIG. 4 is a view, similar to FIG. 2, of a modified blade ring support.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawing, particularly to FIGURE 1, the structure shown therein comprises a turbine outer cylinder or casing 8, with only the base portion 10 being shown in FIGURE 1, and a plurality of blade rings 12 mounted inside the turbine casing. The turbine casing is divided along a horizontal plane PP into a base portion 10 and a cover portion 11 (see FIG. 2) which may be attached to the base portion 10 by means of bolts threaded into holes 14 in the base portion. Likewise, the blade rings 12 are each divided along the horizontal plane PP into a lower half portion 16 and an upper half portion 18. The upper portion 18 is attached to the lower portion 16 by means of bolts 20. Each blade ring 12 contains a plurality of circular rows of stationary blades 22 which cooperate with blades carried by the turbine rotor (not shown) which extends through the turbine along the longitudinal axis LL and is supported by suitable bearings (not shown) in the casing 8. The number of blade rings provided depends upon the size of the tur bine and the number of expansion stages.

In order to provide for diiferential thermal expansion bet-ween the blade rings and the casing, each blade ring 12 is supported on horizontally oppositely disposed dowel pins 24 secured in the lower portion 16 of the blade ring. The dowel pins 24 extend outwardly horizontally in a plane parallel to the vertical plane of the ring into horizontally oppositely disposed recesses 26 in the base 10 of the casing 8. The dowel pins 24 are disposed in the recesses for axially slidable movement, thereby permit ting radial thermal expansion between the blade ring and the casing to occur without stress therein.

As shown more clearly in FIGS. 2 and 3, each dowel pin 24 rests on a fiat liner 28 disposed at the bottom of the recess 26 and attached to the casing 10 by screws 30. The dowel pin 24 has a circular tapered portion 32 received in a tapered opening 34 in the lower portion 16 of the blade ring.

In order to provide adjustable elevation alignment of the blade ring relative to the outer cylinder or casing, the head of each dowel pin 24 has a plurality of, in this case, four flat surfaces 36, 38, 40 and 42 as shown in FIG. 3. Each surface is machined to a different dimension from the dowel pin centerline. By way of example, if the dimension A is considered to be 1.000 inches, the dimension of B may be 1.005 inches, the dimension C may be 1.010 inches and the dimension D may be 1.015 inches. Thus, each dowel pin may be rotated during assembly to select the dimension providing the required elevation of the blade ring for proper clearance between the blades 22 in the ring and the blades carried by the turbine rotor which rotates about the longitudinal axis L-L.

As shown, the surface 40 of the dowel pin 24 rests on the liner 28 with the surface 36 being engaged by a liner 44 retained in the recess 26 by screws 46. Since the surface 36, which is the shortest distance from the centerline of the dowel pin, is opposite the surface 40, which is the greatest distance from the dowel centerline, the liner 44 engages the head of the dowel pin to prevent riding-up of the blade ring. Since the sum of the dimensions B and C (1.005+1.010) equals the sum )f the dmiensions A and D (1000+ 1.015) the liner 44 will also engage the head of the dowel pin when either of the surfaces 38 or 42 is resting, on the liner 28 at the bottom of the recess 26. In this manner compensation may be made for manufacturing inaccuracy by rotating the dowel pins 24 to secure the desired elevational alignment of the blade ring. Likewise, compensation may be made for Wear of the supporting parts by replacing the liners 28 and 44.

The dowel pin 24 may be secured in the tapered openng 34 by the friction of the tapered fit. If desired, how- :ver, a locking pin 48 may be inserted into one of four radial holes 50 in the dowel pin to secure the pin. The rioles 50 correspond with the four flat surfaces on the lead of the dowel pin. The locking pin 48 may be thread- :d into the lower portion 16 of the blade ring.

In order to assist in removing the dowel pin 24 from :he opening 34,' for example during service or repair, t passageway 52 is provided from each opening 50 to he inner end of the dowel pin '24, the tapered portion )f which is shorter than the depth of the opening 34 provide a chamber 54 between the inner end of the lowel pin and the inner end of the opening 34. The ocking pin 48 may be removed and a proper fitting uti ized in its place to inject a liquid into the chamber 54 .hrough the communicating passageway 52 to apply iydraulic pressure on the inner end of the dowel pin to assist in removing the dowel pin.

In the modification of the invention shown in FIG. 4, t cylindrical opening 34 is provided for the dowel pin 24- which is threaded into the opening 34' to retain the )in in the opening. The head of the dowel pin 24 is :onstructed in the manner hereinbefore described and nay be rotated to secure the desired elevation of the )lade ring. The liners 28' and 44', which are similar to he liners 28 and 44, respectively, but of different dinensions, cooperate with the head of the dowel pin 24' n the manner hereinbefore described to permit diifer- :ntial thermal expansion between the blade ring and he turbine casing and prevent riding-up of the blade ring. The liners 28 and 44 are retained in position by screws to and 46, respectively.

From the foregoing description, it is apparent that the nvention provides an improved arrangement for sup- :orting blade rings in a turbine casing in a manner to 0 provide for differential thermal expansion between the lade rings and the outer cylinder or casing of the turine, Also, provision is made for adjusting the elevaion alignment of the blade rings relative to the casing o maintain proper clearance between the stationary tlades of the turbine and the blades carried by the rotor f the turbine which rotates about the longitudinal axis f the turbine. The supporting structure is relatively sim- -le and it is relatively inexpensive to manufacture and nstall.

.Since numerous changes may be made in the above-. described construction and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all subject matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. In an elastic fluid utilizing machine of the axial flow type, in combination,

a casing divided along a horizontal plane into a base portion and a cover portion,

a blade ring disposed inside the casing and divided along a horizontal plane into upper and lower portions,

said base portion having horizontally oppositely disposed recesses therein,

horizontally oppositely disposed dowel pins having generally circular portions secured in the lower portion of the blade ring,

Said dowel pins extending outwardly horizontally into said recesses to slidably support the blade ring, the circular portion of at least one of said dowel pins being shorter than the depth of the opening for the pin and jointly forms a chamber therewith, and

a passageway communicating with said chamber to permit injection of a pressurized liquid into the chamber to apply hydraulic pressure on the inner end of the pin to assist in removing the pin.

2. The combination defined in claim 1, wherein the head of each dowel pin has a plurality of fiat sur faces each machined to a different dimension from the dowel centerline.

3. The combination defined in claim 1, including liners disposed in said recesses upon Which the dowel pins rest.

4. The combination defined in claim 2, including a liner at the bottom of each recess upon which a fiat surface of a dowel pin rests, and

another liner at the top of each recess cooperating with a fiat surface of the dowel pin opposite the flat surface at the bottom of the pin and retaining said dowel pin against upward movement.

5. The combination defined in claim 1, wherein the dowel pins have a taper fit in openings in the blade ring.

6. The combination defined in claim 1, including a locking pin inserted into the circular portion of each dowel pin.

7. The combination defined in claim 1, wherein each dowel pin is retained in the blade ring by a portion threaded into the blade ring.

8. The combination defined in claim 1, including means for attaching the upper portion of the blade ring to the lower portion.

9. The combination defined in claim 5, wherein the head of each doWel pin has a plurality of fiat surfaces each machined to a different dimension from the dowel centerline,

the taperedportion of each dowel pin has radial holes corresponding with the flat surfaces on its head, and

a locking pin inserted into one of the holes.

10. The combination defined in claim 1, wherein the circular portion of thedowel pin has a radial hole therein, and

the dowel pin has a groove therein communicating between the radial hole and the chamber, said hole and said groove forming the passageway.

11. The combination defined in claim 10, wherein a locking pin is inserted in the radial hole, and

the locking pin is removable to permit the application of the hydraulic pressure.

12. The combination defined in claim 4, wherein the head of the dowel pin has at least two pairs of opposed surfaces and the distance between each pair is substantially identical.

6 13. The combination defined in claim 12, wherein FOREIGN PATENTS the head of the dowel pin is of square shape. 1,088,067 9/1960 Germany 369,680 3/1932 Great Britain. References Cited 744,994 2/1956 Great Britain. UNITED STATES PATENTS 5 3,141,651 7/1964 Moyen EVERETTE A. POWELL, 111., Primary Examiner 3,147,952 9/1964 Ladner. 3,169,748 2/1965 Howard et a1. 

